ECap AC

The ECap AC Audio Coupling & Signal Cap RAW are bipolar aluminum electrolytic capacitors for audio applications in which film capacitors cannot sensibly be used for reasons of space or cost. Their foil surface is roughened, and thus enlarged, by a special etching process. A very thin, continuous, insulating aluminum oxide layer forms on the surface of the aluminum foil and acts as the dielectric. The counter-electrode to the aluminum foil is formed by a conductive liquid, the electrolyte. The roughened electrode surface is very large, and the dielectric formed on this surface by a chemical process is very thin. Since capacitance is proportional to the effective surface area and inversely proportional to the thickness of the dielectric, this yields very compact and inexpensive audio capacitors for coupling and signal tasks, whose capacitance can be relatively high for their compact size. As bipolar electrolytic capacitors they withstand AC voltage and are therefore suitable for music signals.

Technical Properties

Electrical Properties

Bipolar construction (AC-voltage-proof)

Enables use in the signal path with alternating-current signals – in contrast to polarized electrolytic capacitors.

Etched (“rough”) aluminum foil

Enlarged surface → high capacitance in a small package with a good price/performance ratio.

High capacitances economically achievable

Particularly suitable when large capacitance values are needed but film capacitors would be too large or too expensive.

Macro-Microphonics

Compact design thanks to the enlarged foil surface

A smaller space requirement facilitates mechanically favorable placement in the assembly (e.g. shorter paths, stable fastening).

Practical focus: mechanically solid mounting

As with all electrolytic capacitors: stable fastening and decoupled mounting help minimize mechanical excitation.

Micro-Microphonics

Note on application

In practice, micro-microphonic effects are largely co-determined by construction, fastening and environmental influences; the ECap AC are conceived as an economical signal/coupling solution.

Sonic Character

The ECap AC RAW are designed for practical, stable signal transmission at high capacitances – wherever film capacitors are not feasible. In the sound picture, functional, musically clean coupling is paramount: reliable, uncomplicated and economical, without the claim of replacing a film solution with the finest resolution.

Applications

• Audio coupling (AC coupling) in signal paths when film capacitors do not fit
• Signal and filter tasks with high capacitance values in limited space
• General audio applications calling for a compact, price-conscious solution for AC-voltage-proof capacitors